Known in the art is a centrifugal fluid cleaner comprising a vertical stationarily attached hollow shaft provided with conduits for the supply and removal of fluid. Mounted on the shaft through the medium of friction bearings is a cylindrical rotor which comprises a casing, a sleeve with a helical band attached thereto, lower and upper impellers arranged under and above the helix, respectively.
A number of equispaced spacers are installed parallel to the hollow shaft between adjacent turns of the helix in a radial array to form axial slots within the helical band. The mixture of fluid and solid particles is caused to enter the slots through cavities formed between the lower impeller disk and respective end face of the helical band, said cavities communicating with the shaft interior space via holes in the said shaft.
Under the effect of centrifugal force the solid particles are separated from the fluid, being thrown onto the band surfaces.
The purified fluid is drawn from the slots into a chamber formed between the casing upper wall and the top end face of the helical band, accomodating a pressure disk and upper impeller and communicating with the outlet conduit in the hollow shaft.
The separation of solid particles of any size from the polluted fluid in a centrifugal cleaner of such design takes place only in the slots of the helical band, which causes clogging of the slots with sludge, if the contents of contaminants is high, with a resultant deterioration of the efficiency of the purification process. To remove accumulated sludge, it is necessary to strip the cleaner into the component parts and wash the latter. In the above described centrifugal cleaner air is trapped in the upper part when the cleaner is being primed with fluid. It is mandatory to bleed that air prior to starting the cleaner, for which purpose a plugged hole is provided in the uppermost part of the casing. The air bleeding operation complicates preparation of the cleaner for service run.